1. Field of the Invention
The present invention relates to a rear structure of an all terrain vehicle (ATV).
2. The Related Art
An engine unit, in which a belt (belt-type) continuously variable transmission (CVT) is formed integrally with an engine main body and which is mounted in a saddle type all terrain vehicle (ATV), a motor-cycle or the like, includes a vehicle transmission cooling structure.
The vehicle transmission cooling structure introduces, as cooling air, fresh air from an outside (external air) into, for example, a belt case in which the transmission is accommodated through, for example, a duct to cool members arranged in the belt case, and discharges the cooling air into the atmospheric air through, for example, a duct so as to prevent heat generated by the operation of the transmission from adversely influencing a V-belt, a seal member, etc.
A rigid exhaust dust formed of, for example, synthetic resin, is conventionally attached to an exhaust port provided in a rear portion of the belt case through an elastic body such as rubber, and fixed to a vehicle body frame. In addition, a cooling air exhaust port of the exhaust duct is set at a position higher than that of an exhaust port of an exhaust muffler so that water does not enter the belt case while the vehicle moves at the waterside or in a rainy day (see, for example, Japanese Patent Laid-Open (JP-A) Publication Nos. 2003-90417 and 2003-56679).
A rear wheel driving system such as a rear wheel final reduction gear or a rear wheel differential reduction gear includes a breather device, and a breather hose for discharging a blow-by gas. The breather hose is arranged from the rear wheel driving system to an upper portion of a vehicle body at a depth equal to or larger than the depth of water at which the vehicle can move and then bent downward so as to prevent water or the like from entering the hose during an intake operation (see, for example, Japanese patent Laid-Open (JP-A) No. HEI 9-328088).
However, if the exhaust duct is arranged from the belt case to the position higher than the exhaust port of the exhaust muffler, the exhaust duct becomes large in size. If the vehicle has an independent rear wheel suspension system, a structure of a rear portion of the vehicle body frame will become complicated. As a result, it is difficult to assemble the large-sized exhaust duct into the vehicle body. For this reason, it is sometimes necessary to provide an opening for assembling the exhaust duct to a portion of the vehicle body frame or to make partially detachable the vehicle body frame.
Meanwhile, when the breather hose is arranged and fixed, the breather hose is fixed along a vehicle body component such as the vehicle body frame using another component such as a clamp and the like. This disadvantageously increases the number of assembling steps and the number of components, resulting in cost-up.